A man walks past a stock quotation board in front of a securities company in Tokyo on May 12, 2017.

Japan on Thursday said first quarter GDP rose a more than expected 0.5 percent on quarter and 2.2 percent at an annual pace.

A poll ahead of the data by Reuters showed analysts expected a 0.4 percent quarterly gain and a 1.7 percent annual pace. The data showed the fifth straight quarter of growth and the fastest pace since the first quarter of 2016.

"It's good, but probably we may not see a continuation of this level of growth for the next quarters," Sayuri Shirai, a former Bank of Japan board member, told CNBC's "Squawk Box" on Thursday.

She noted that much of the improvement was export-driven, but it wasn't clear whether that would continue, particularly as demand for autos in the U.S. appeared to be dropping. Real wages also were losing ground, she said.